The AMOEBA clustering method finds irregularly shaped, contiguous clusters in spatial datasets. The code is provided as an ArcToolbox, and the scripting is done in Python.
Point Pattern Analysis or PPA is a C program that performs a number of spatial analysis routines on univariate spatial data. These include a number of point pattern analysis techniques, such as nearest neighbor methods and Ripley's K. The program also computes a number of local and global spatial autocorrelation statistics (I,c,G). In all cases, a three column ASCII file (x,y,z) is required. A spatial weights matrix may be used to compute Moran's I and Geary's c. Please download the manual for a complete listing and an example application of each method. Additionally, the Getis filtering method can be computed in the DOS/Windows version of the program (not in manual).
The program was developed by Dong Mei Chen, Arthur Getis, and Jared Aldstadt. It is freely available from this website. Source code is available upon request.
There is also a web interface to PPA maintained by Andy Long at Northern Kentucky University.